Many electronic and other devices require a user to interact with or control the device by depressing keys or otherwise activating input regions on a keyboard or other input device. Keyboards or other input devices are often marked with visual indicia to allow a user to know which key must be depressed or activated. Computers, for example, are controlled using keyboards having a number of keys with alpha-numeric characters. Such visual indicia, however, is not recognizable by a visually impaired individual, and many of these devices are not adapted for use by visually impaired individuals. Thus, using input devices, such as computer keyboards, and other similar devices, such as musical instruments, is difficult and may even be impossible for many visually impaired individuals.
Computers can be useful tools for communicating with and/or teaching individuals with disabilities, if the individuals have a way of interacting with the computer. Computer keyboards have been designed for individuals with motor difficulties from such disabilities as cerebral palsy, mental retardation, and brain trauma. One example is the keyboard available from Intellitools, Inc. of Novato, Calif. under the name INTELLIKEYS.RTM., which is described in greater detail in U.S. Pat. No. 5,450,078, entitled Membrane Computer Keyboard and Method and incorporated herein by reference. This and other such keyboards, however, have had limited applications for visually impaired individuals.
One way of adapting a keyboard or input device for use by visually impaired individuals is to provide an overlay system to be placed over the keyboard or input device. One example of such an overlay system is disclosed in greater detail in U.S. Pat. No. 5,536,170 issued to the inventor of the present invention and incorporated herein by reference. The overlay has depressible portions that align with the keys or other pressure sensitive regions of the keyboard or input device. This overlay system is used with tactile recognition (e.g., Braille) blocks, such as those disclosed in U.S. Pat. Nos. 4,880,384 and 5,391,078 issued to the inventor of the present invention and incorporated herein by reference. The blocks are removably coupled to the depressible portions of the overlay such that the visually impaired individual can tactilly discern the character or indicia on the block and activate the appropriate key or input region of the input device by depressing the block and corresponding depressible portion.
Although this overlay system disclosed in U.S. Pat. No. 5,536,170 provides an interchangeable system that allows visually impaired individuals to use keyboards or other similar devices, there are some limitations. This overlay system provides for keyboard activation by depressing the tactile recognition blocks downward. Many visually impaired individuals, especially those first learning how to read Braille, will inadvertently activate the key when touching the Braille or other tactilly recognizable region and attempting to tactilly discern the Braille character. The keys may also be inadvertently activated when coupling and removing the tactile blocks. Thus, an input device or overlay that requires downward depression of a key is not ideally suited for visually impaired individuals.
Accordingly, a need exists for a tactile recognition input device, such as a computer keyboard, that reduces the tendency of visually impaired individuals to inadvertently activate the keys. There is also a need for a tactile recognition overlay to adapt existing keyboards or input devices for use by visually impaired individuals with a reduced tendency to inadvertently activate the keys.